Introduction: Zygomatic complex fractures or the tetrapod fractures are common to occur followed by the nasal bone fractures because of its prominent location. At the same time, it is difficult to obtain perfect reduction and contour postoperatively because of its complex involvement with four bones namely maxillary, temporal, orbital and greater wing of sphenoid bone. Various classifications have been put forward for better understanding and planning of treatment protocol. Aim: This study aims at comparing the following variables after reduction and fixation of fracture zygomatic complex; 1. Esthetics 2. Restoration of anatomical form 3. Occlusion 4. Function 5. Neurological deficits. Materials and Methods: Twenty patients were selected following a clinical and radiographic examination of fracture of the zygomatic complex. Reduction techniques used were Gillie's, Dingman's lateral eyebrow, and upper buccal sulcus approaches. Fixation was done at single-point or two-point or three-point protocol by transosseous wiring or miniplate osteosynthesis. Results: Among the twenty cases treated, all were males. Age distribution of the patients was between 20-60 years with a mean age of 39.5 years. There was facial asymmetry in four cases postoperatively and two among them did not follow postoperative instructions. Conclusions: Closed reduction namely Gillie's temporal approach was found to be the best reduction technique and the protocol of three point, miniplate fixation was effective in terms of stability and relapse.

Management of facial trauma has undergone a revolution in the past decade because of the introduction of better diagnostic tools, improved surgical approaches and availability of improved fixation system. Associated with these technical and surgical advances, is the in-depth understanding of pathophysiology of fractures. While fractures of zygomatic bone are rare, over pneumatization of the maxillary sinus may weaken it sufficiently to predispose towards fracture. The fracture complex most frequently noted, occurs at the zygomaticomaxillary suture line involving the infraorbital rim and floor of the orbit and at the zygomaticofrontal suture line involving the lateral synchondrosis of the orbital cavity and, rarely, the zygomatic buttress region. [1]

Zygomatic complex fractures, many time present challenging diagnostic and reconstructive problems for the surgeons. The aim of any treatment method is to give the best results with the least morbidity. [2],[3] Various methods for the repair of zygomatic complex fractures have been advocated by many surgeons with emphasis on the types of incision, methods of fixation and at times even reconstruction. The treatment of fractured zygomatic complex are carried out by various approaches intra orally as well as extra orally. Knight and North [4],[5] in 1961 classified "malar" fractures according to the type of displacement to develop a more rational approach to their treatment.

Out of a large number of facial trauma cases routinely seen in the department, both as outpatients and inpatients, a selective list of twenty patients with zygomatic complex fractures, were selected for treating by various modalities for reduction and fixation of the fracture segments by miniplate osteosynthesis and transosseous wire osteosynthesis. Our department currently does not use compression-plating system because of the following disadvantages:

The amount of compression was variable and thus excessive compression may cause bone lysis

Moreover, stress shielding may occur in compression plating.

Thus, miniplate and transosseous wire osteosynthesis are now routinely used for internal fixation.

Materials and Methods

Materials

Twenty patients were selected for this study after obtaining approval of the institutional ethics committee and informed consent of the participants. All were between the age group of 20 to 40 yrs. The clinical examination was performed using standard protocols.

All the patients were generally examined and treated for associated injuries [Lefort fractures of maxilla, mandibular fractures]

All the patients were subjected to routine investigation, which includes routine blood investigation, radiographs (PNS and OPG)

None of the patient was taken up for surgery immediately after the trauma. The time period was 4 to 7 days after the trauma. All of the patients included in this study had displaced fracture zygoma with or without associated facial bone fractures.

Methods

Closed reduction technique

Gillie's temporal approach

Gillie's et al., in 1927 described this approach. Under general anesthesia, oroendotracheal intubation, a 3 × 3 cm area of hair is shaved approximately 2.5 cms above and anterior to the helix of the ear. Frequently the bifurcation of the superficial temporal artery is visible once the area is shaved. A 2-cm incision is made approximately between the bifurcations of the superficial vessels at approximately 45 degrees to the upper limit of the attachment of the external ear. The incision is made through the skin and subcutaneous tissue at an angle running from anterosuperior to posteroinferior area. This incision is carried down until the white glistening surface of the temporal fascia is visualized. At this level, one should be above the point were the temporal fascia splits into two layers, one attaching lateral and one medial to the zygomatic arch.

A second deeper incision is carefully made along the full length of the skin incision until the temporalis muscle bulge is visible. The temporalis muscle is the key structure in this dissection. A flat instrument such as a large freer elevator or the broad end of no. 9 periosteal elevator is then inserted between the temporalis muscle and temporalis fascia. The instrument is swept back and forth while the tip is moved inferiorly to the medial aspect of the zygomatic arch and infra temporal surface of the body of zygoma. In medially displaced fractures, it may be difficult to pass the instrument to the zygomatic arch. In this instance, the tip of the instrument must be passed medially until the medial aspect of zygomatic arch is reached.

The Rowe's zygomatic elevator is then passed beneath the periosteal elevator as it is withdrawn. This elevator has a flat blade on its working end for insertion medial to zygomatic arch and body. It has two handles for grasping during use. The first handle is in a direct line with the working end and is used primarily for stabilization. The second handle is on the external lifting lever, which is attached to the area of stabilizing handle. When the stabilizing handle is kept in position and lifting handle as activated, the working blade can generate large amounts of force beneath the zygoma. With this feature the surgeon can constantly be aware of the depth of insertion of the working blade by collapsing the hinge between the two arms and seeing whether the external handle lies in relation to the zygoma.

Once the Rowe's zygomatic elevator is at the proper depth, the external handle is elevated while the other handle stabilizes the working blade position. Firm anterior, superior and lateral elevation is applied to the body of the zygoma and arch. An audible crunch or crack usually accompanies the elevation. Later the instruments working blade should be swept posteriorly and laterally, reducing or "ironing out" any zygomatic arch fractures. Once verification of adequate reduction and resistance to displacement has been accomplished, the elevator is withdrawn and the incision is closed in one or two layers with vicryl or chromic catgut. Patient recovery was uneventful. In unstable fracture after reduction, miniplate fixation can be done in frontozygomatic suture region through lateral eyebrow approach [Figure 1].

Dingman in 1964 described a supraorbital lateral eyebrow approach. Under general anesthesia, nasoendotracheal intubation prior to skin incision, the lateral orbital rim was palpated to confirm the location of fracture site, which is located at the frontozygomatic suture. The skin is kept taut over the orbital rim using two fingers. A 1.5-cm long incision is made at the lateral portion of the eyebrow. The dissection is then carried out sharply and bluntly through the subcutaneous tissue down to the bone. The periosteum is incised and reflected from the bone and the fracture is visualized at frontozygomatic suture line. A Rowe's zygomatic elevator is passed through the incision behind and lateral to orbital margin into temporal fossa. The elevator is passed behind the temporal aponeurosis, which is the attachment of deep temporal fascia adjacent to the frontal process of zygoma. The elevator may be passed either under the zygomatic arch to lift it laterally or under the body of zygoma to lift it upward, forward, laterally and outward movement. The displaced segments were repositioned into position and during reposition, the zygoma was palpated through the skin in the infraorbital margin for the continuity of the rim in case of fracture involving the infra orbital rim and guided into position.

Drill holes were placed through the bone 5 mm to each side of fracture sites after reduction at frontozygomatic suture using hand piece with bur and saline. 26-gauge stainless steel wires were passed through the holes and twisted to maintain the bony fragments in anatomical reduction. Among 20 cases which were treated in this study, in 6 cases transosseous wiring was done in the frontozygomatic suture and in 1 case 2 holes were drilled on either side of the fragment and horizontal mattress wiring was done in the frontozygomatic suture. In 10 cases after reducing the reduced fragments into anatomical position, 2 drill holes were placed in the bone on either side of the fracture site at frontozygomatic suture using drill and 4-hole miniplate was accurately contoured. 2-mm screws were inserted through the previously drilled holes and screws were tightened. Wound was well irrigated with saline. The wound was closed in layers, periosteum with 3-0 chromic catgut and skin with 4-0 black silk. Patient recovery was uneventful [Figure 2].

Keen in 1909, described an intra oral approach for zygomatic complex reduction. A small incision approximately 1 cm is made in the mucobuccal fold, just beneath the zygomatic buttress of the maxilla. The incision can be made from anterior to posterior or from medial to lateral and should extend through the mucosa, sub mucosa and buccinator muscle fibers. The sharp end of no. 9 periosteal elevator or curved freer elevator or Taylor monk's elevator is inserted into the incision and using a side-to-side sweeping motion, the surgeon makes contact with infratemporal surface of maxilla, zygoma and the zygomatic arch and dissects the tissue in a supraperiosteal manner. A heavier instrument such as Rowe's zygomatic elevator can then be inserted behind the infratemporal surface of zygoma and using superior, lateral and anterior force, the surgeon reduces the bone. The use of one hand over the side of the face to assist in the reduction is extremely helpful. One should take care to avoid using the anterior maxilla as a point of fulcrum. In cases of zygomatic buttress fracture, the fragments can be aligned and fixed with 4-hole miniplate after adaptation and stabilized with screws. Wound was well irrigated with saline. The incision in the mucobuccal fold was sutured with catgut. In 6 cases, this approach was done [Figure 3] and [Figure 4].

The infra orbital rim incision is made in the eyelid several millimeters above the infraorbital rim. If this incision is made in cheek skin, it produces a noticeable scar. The incision should not be carried lateral to the cornea as edema of the eyelid may result. This incision provides poorer lateral exposure than incisions made more superiorly in the lower eyelid. Care must be taken to stay in the plane between the orbicularis muscle and the orbital septum. Damage to the orbicularis muscle or to the orbital septum results in vertical shortening of the lid. Blunt dissection of the orbicularis muscle is carried out till the periosteum of the inferior orbital rim is reached. Another incision is made through the periosteum and reflected. The infraorbital rim, zygomaticomaxillary suture lines can then be visualized for the continuity and if there is any discontinuity of the infra orbital rim, the rim is either reduced through Dingman's lateral eyebrow approach or Gillie's temporal approach or intra oral upper buccal sulcus approach. After reduction and obtaining the continuity of the inferior orbital rim, the fragments were stabilized with miniplate osteosynthesis or transosseous wiring (figure of eight). The wound is well irrigated with saline and closed by 2 layers - the muscle layer with catgut and the skin by proline sutures. Among 20 cases, 2 cases were done with this approach and stabilized with a 4-hole miniplate with screws at the infraorbital rim and at the zygomaticosuture line. Reduction was done through lateral eyebrow approach [Figure 5].

Twenty cases of zygomatic complex fractures were treated [Table 1]. Out of these, 15 cases were isolated zygomatic complex fractures. One case required no treatment. Five patients were associated with other facial bone fractures. Among the 20 cases treated, in 10 cases the principle of miniplate osteosynthesis was applied for fixation of fractures following reduction and in one case, the principle of transosseous wiring was applied for fixation after reduction. In four cases, combination of miniplate osteosynthesis and transosseous wiring was applied for fixation after reduction. In two cases, transosseous wiring at the frontozygomatic suture with lateral suspension wiring was done in association with other facial bone fractures. Nine patients required one-point fixation following reduction and four patients required two-point fixations after reduction and two patients required three-point fixations after reduction. Three patients required bilateral open reduction and transosseous wiring at frontozygomatic suture through Dingman's lateral eyebrow approach following reduction. Three patients required closed reduction through Gillie's approach and miniplate fixation at frontozygomatic suture through Dingman's lateral eyebrow approach. Two patients required closed reduction through Gillie's approach without fixation. Four patients required open reduction and transosseous wiring at frontozygomatic suture following reduction through Dingman's lateral eyebrow approach and six patients required open reduction and miniplate fixation at frontozygomatic suture following reduction through Dingman's lateral eyebrow approach.

All the 20 cases treated were males. Age distribution of the patients was between 20-60 years with a mean age of 39.5 years [Table 2]. There was facial asymmetry in four cases postoperatively and two among them did not follow postoperative instructions.

Many patients had facial asymmetry with deranged occlusion preoperatively [Table 3]. Postoperatively three patients had transient trismus. There was no complaint of pain in the region of fixation during follow up after a month. Occlusion was corrected in cases were there was derangement of occlusion preoperatively [Table 4]. There was no evidence of postoperative infection. There was no evidence of neurological deficits post operatively in the form of infraorbital anaesthesia in any of the cases in this study.

Zygomatic complex fractures, many at times present challenging diagnostic and reconstructive problems for the surgeon. [2] Since the midface injuries heal rapidly because of the nature of the bone and consolidate in three weeks even in position other than normal anatomical consideration. Stoll and Schilli, [8] stressed the importance of early intervention to achieve cosmetic and functional results. [9] Management of unstable, so-called tripod, non-comminuted malar fracture is open to debate according to Fischer-Brandies and Dielurt, [10],[11] the treatment varies with the amount of damage sustained, but nearly always consists of reduction followed by fixation. Various methods for the repair of zygomatic complex have been advocated by many surgeons with emphasis on the type of incisions, methods of fixation, and at times even reconstruction. [12] The aim of any treatment method is to give best result with least morbidity. [2] In order to obtain standardization of treatment, several classification of zygomatic complex has evolved, based on clinical and radiological examinations. These classifications suggest a prediction with regards to post-reduction stability and thereby emphasize the specific treatment advisable for each case. [12],[13]

The principles of management of the zygomatic complex fractures are similar to the principles of management of fractures elsewhere in the skeletal system. [3],[14] Many methods of treating zygomatic complex fractures have been described in the literature and at the same time many controversies do exist.

One of the popular treatment modalities involves the reduction of fractured fragments through Dingman's approach into their anatomical relationship to provide bony contact, proper alignment by the use of wire osteosynthesis. Excessive force and slight mobility of the fracture fragments impedes healing because these factors may stimulate non-osteogenic cells to invade the area resulting in fibrous union. Therefore, in addition to accurate reduction, fixation is often needed to achieve healing of fractured bone [14] (Zigmunt.W.Pozatek et al., 1973) - viz,

The lacerated tissue in the fracture that may hinder proper reduction can readily be released and retracted

The elevator would be in direct contact with the large mass of bone and thus the force of reduction is exerted in more directions because the fracture is directly exposed with this incision

An assessment of anatomical reduction can be made intraoperatively and an opportunity for fixation at the time of reduction is offered. In view of the above advantages, reduction and fixation by transosseous wiring or by miniplates through Dingman's incision was followed in 15 cases in the department during the year 1988-2001. Our findings agree with the findings of Zigmunt.W.Pozatek et al.,[14] who advocated elevation of zygoma and fixation by Dingman's incision (Lateral eyebrow approach). Since the incision is made almost entirely within the confines of eyebrow, so that the scar is imperceptible. The disadvantages of Dingman's incision according to Edward Ellis, [15] is that it is difficult to generate large amount of force, especially in the superior direction. But this disadvantage was not encountered in our present study.

Ogden G.R [16],[17],[18] in his analysis of 105 cases of fractures of zygomatic complex treated by Gillie's temporal approach and found that majority of cases (92%) did not require open reduction. He is of the opinion that Gillie's method of treating zygomatic complex fracture is ideal because of minimal morbidity and short duration of anesthesia. The Gillie's method offers the advantage of being quick (thereby shortening the duration of anesthesia), decreasing the possibility of facial nerve damage or direct trauma to the globe by instruments inserted to protect the eye and not associated with visible scar (the scar being within the hairline). Further fixation can be performed at the time of operation, if found to be necessary and depends upon the type of fracture which may need two- or three-point fixation. The isolated arch fracture can be excellently reduced with this approach, which does not require any fixation unless comminuted.

Open reduction and fixation by transosseous wiring was done in seven cases in relation to frontozygomatic suture via Dingman's Lateral eyebrow approach. Our study in seven cases correlates with the study conducted by Esben Kaastad et al.,[12] who used transosseous wiring at the frontozygomatic suture. In one case which was comminuted zygomatic complex fracture, reduction and fixation was done by transosseous wiring at frontozygomatic suture via Dingman's Lateral eyebrow incision and two 4-hole miniplates were fixed, one at the infraorbital rim and the other at the comminuted zygomaticomaxillary suture via the low infraorbital approach and were held in anatomical position which is in accordance with the study conducted by Dingman and Alling (1954), [19] Grimm (1961), Spiessel and Schroll (1974), Finlay et al., [20] Manson et al.,[21],[22] and Ian.T.Jackson et al. [23],[24]

The low infraorbital approach has the following advantages:

The incision is simple, since there is a short and direct path to the infraorbital margin

The avoidance of the orbital septum and periorbital fat which is usually assured in this location

There is an almost non-existent incidence of postoperative ectropion and

The incision can be extended both medially and laterally, if necessary, to provide improved access. Fixation in the zygomaticomaxillary suture line is more useful through this approach without any complication according to Edward Ellis. [15]

The above authors cite the following advantages, a) Procedure is easy to perform b) Very little foreign material is necessary for osteosynthesis. But Paul.N.Manson, [21] Karlan and Cassini disputed the claim of the above authors stating that wire osteosynthesis produces one-dimensional force of apposition, some rotation is allowed, since three-dimensional stability is not produced by single-wire fixation when as little as 2.25 kg of force was applied. They also stated that it is not functionally stable since the diameter of the bur hole is greater than that of the wire used, and there is little contact between wire and bone, twisting the wire ligatures generates uncontrollable pressure which leads to tearing of suture in thin bones. [12]

The recent application of rigid fixation techniques to zygomatic complex fractures has out dated all of the older techniques of fixation. There is no better method of providing stable fixation to an unstable zygomatic fracture than to rigidly secure it internally. [12] The obvious advantage to bone plate is that it produces stabilization in three planes. The technique of miniplate osteosynthesis for stable fixation of the zygomatic bone fractures. Ian.T.Jackson et al.,[23] used champy miniplates in the treatment of midface and zygomatic bone fractures.

In the present study, there was no displacement of the zygoma after fixation at the frontozygomatic suture using a miniplate as it gives stability in three planes and the facial symmetry was corrected in all 17 cases except for two cases were the patient did not follow postoperative instructions. Ian.T.Jackson et al.,[23] and Kunio Ikemura et al., [25],[26] concluded that there was no displacement of zygoma after fixation at frontozygomatic suture, using a miniplate, as the bone plate gives stability in three planes, three- or four-point fixation of zygoma is not necessary except for complex and comminuted fractures.

The masseter muscle with its attachment along the inferior surface of the zygomatic arch has often been implicated as a primary cause for post reduction displacement of the fractured zygomatic complex. It is assumed that to be capable of exerting sufficient inferiorly directed force on the fractured zygoma to cause movement, even after surgical insertion of fixation devices. This problem has been extensively reviewed and surgeons prefer using three- or four-point fixation instead of one- or two-point fixation as it offers more accurate reduction and less postsurgical displacement. [27],[28],[29],[30]

With regard to healing of fracture fragments, ophthalmic signs like Diplopia, our results obtained were in accordance with the results of Korlan and Cassini. [12] No neurological deficits were found in this study which correlates with the studies by Ian.T.Jackson et al.,[23] who reported that after miniplate osteosynthesis neurological complications were about 50% lower than those treated by wire osteosynthesis.

In most of the above cases during reduction, bradycardia was produced during manipulation of zygomatic arch and midface fractures, which correlates to J.Loewinger et al. [31],[32] The possible mechanism is due to oculo cardiac reflex. The afferent pathway is through the short ciliary nerves and the ophthalmic division of the trigeminal nerve to the Gasserian ganglion More Details and hence to the main sensory nucleus of the trigeminal nerve. The efferent pathway is via the vagus nerve, which release acetyl choline producing bradychardia by increasing the parasympathetic tone. Further more bradychardia disappeared promptly when the surgical stimulus ceased and without the administration of supplementary oxygen or artificial ventilation. This reflex correlates with Vance Robideaux et al.,[33] who reported a case of oculo cardiac reflex caused by midface disimpaction. This reflex is known to be a potential hazard of ophthalmic surgery. This reflex should be recognized as a potential hazard of midface disimpaction. Mild bradycardia was managed by the cessation of the stimulus whereas severe bradycardia was managed by the administration of 0.6 mg/IV atropine and 6 μg/IV of epinephrine was administered if there was no response to atropine. [34]

Conclusion

Different reduction and fixation approaches were done in selected patients. The best reduction technique is by Gillie's temporal approach followed by miniplate fixation at -

Osteosynthesis by miniplates is a simple, logical and effective treatment compared to wire osteosynthesis as regard to stability of the fracture segments. This procedure is followed routinely in this department for fractures in this particular region.

Though wire osteosynthesis did give satisfactory results when compared to miniplate osteosynthesis, it is still desirable to use miniplate osteosynthesis, as it would give firmer rigidity.

Most of the cases landed up with slight asymmetry following reduction in the post operative follow-up phase. So we conclude that there is a need for malar augmentation to correct the residual deformity.

Finlay PM, Ward-Booth RP, Moos KF. Morbidity associated with the use of antral packs and external pin in the treatment of the unstable fracture of the zygomatic complex. Br J Oral Maxillofac Surg 1984;22:18-23.